Compositions, which comprise benzoylperoxide as an active ingredient, are considered to be amongst the most effective ones in the treatment of acne vulgaris (see, for example, J. J. Leyden and A. M. Kligman, Drugs, 12, 292-300 (1976)). To improve the effect of benzoylperoxide there are frequently added to the compositions other known anti-acne substances. For example, as described by S. Hurwitz in Cutis 17, 585-590 (1976), there is a substantial increase in the therapeutic effect when benzoylperoxide is used in combination with retinoic acid. Considerable disadvantages of such compositions are, however, that they frequently cause allergic contact dermatitis and/or that they are, in certain cases, extremely irritating and drying, necessitating alteration of either the frequency or the duration of the applications or the concentration of the active ingredients in the composition.
Especially in the treatment of patients with inflammatory lesions, benzoylperoxide is often used in combination with orally administered antibiotics, e.g., tetracycline, erythromycine and the like. However, many questions have been raised concerning the safety of short- and long term use of orally administered antibiotics in the treatment of acne. Moreover, as a general rule, it is desirable to avoid oral therapy in the treatment of skin diseases whenever an effective topical treatment modality is available. Compositions, which are suitable for topical administration and which comprise benzoylperoxide in combination with, for example, erythromycine, are described in French Pat. No. 2,378,523. These compositions are known to reduce the numbers of Propionibacterium acnes, the main organism involved in the acne bearing areas.
W. J. Cunliffe and D. Gould, in British Journal of Clinical Practice, Suppl. to 32 (8), 15 (1978), described an experiment wherein a cream, containing 2% of micronazole nitrate, was tested in the treatment of acne. Although a positive effect was noted it was found that the numbers of Propionibacterium acnes and Staphylococcus epidermidis on the skin were not altered, despite the in vitro activity of micronazole against Propionibacterium acnes.